Liquid scouring cleansers containing abrasives are well known in the art. In general, the cleansers comprise mixtures of surfactants, water and abrasives, and optionally, suspensory materials, such as clays, in order to keep the abrasive stably in suspension. Clark et al, U.S. Pat. No. 4,129,527, proposed pourable detergent compositions in which relatively small-sized abrasive particles (less than 100 mesh size, 150 microns) are combined with amine oxides and alkyl aryl sulfonates. Soft abrasives, e.g., calcite (calcium carbonate) are preferred for use. Chapman, U.S. Pat. No. 4,158,553 describes liquid scouring cleansers containing abrasives having Mohs hardness greater than 3, suspended in a mixture of soaps and anionic and/or nonionic surfactants. Canadian Patent No. 1,048,365 shows a dry, granular detergent composition containing relatively low amounts of abrasives which have relatively large particle sizes (300-850 microns) and, generally, Mohs hardness of greater than about 4. Finally, European patent application No. 22 545 shows a cleaner containing abrasives having very small particle sizes (about 15-150 microns) with a Mohs hardness of about 2-7.
As a general rule, although these aforementioned prior art cleansers may be suitable for use on such hard surfaces as counter tops, tile surfaces and grout, their use may be problematic from the standpoint of application to shiny, metallic surfaces, e.g., aluminum and steel pots and pans. For instance, these types of surfaces can become imbued with difficult-to-remove soils such as baked-on egg yolk (denatured protein) or barbecue sauce (caramelized sweeteners and oil). Cleansers such as those depicted in U.S. Pat. No. 4,129,527, appear to have little effect on such soils, due to their gentle abrading action. On the other hand, cleansers such as those of U.S. Pat. No. 4,158,553 and European patent application No. 21 545, which contain very hard abrasive particles might be effective for removal of the aforementioned problematic stains, but tend to damage or mar shiny aluminum and stainless steel surfaces on typical pots and pans used by consumers.
Nothing in the prior art shows, discloses or teaches that relatively soft abrasive particles having a larger average particle diameter will result in increased cleaning over those cleaners containing relatively soft abrasives with small average particle diameter. The art further does not show, disclose or teach that using relatively soft abrasives having a larger average particle diameter will result in reduced scratching of surfaces which have a tendency to scratch when abraded with most liquid abrasive cleansers containing hard abrasives but still result in at least equal cleaning with these hard abrasive-containing cleansers.
Moreover, nothing in the art shows, discloses or teaches that a triple tiered weight distribution of abrasive particles having a Mohs hardness of about 2-4 is crucial towards obtaining the improved cleaning of the present invention over prior art cleansers using relatively soft abrasives, while minimizing scratching of shiny surfaces which have a tendency to deface when abraded.